The present invention relates to a seal member.
The inventors of the invention proposed a method of producing a carbon nanofiber composite material that improves the dispersibility of carbon nanofibers using an elastomer so that the carbon nanofibers can be uniformly dispersed in the elastomer (see JP-A-2005-97525, for example). According to this method of producing a carbon nanofiber composite material, the elastomer and the carbon nanofibers are mixed, and the dispersibility of the carbon nanofibers that have strong aggregating properties is improved by applying a shear force. Specifically, when mixing the elastomer and the carbon nanofibers, the viscous elastomer enters the space between the carbon nanofibers while specific portions of the elastomer are bonded to highly active sites of the carbon nanofibers through chemical interaction. When a high shear force is applied to the mixture of the carbon nanofibers and the elastomer having an appropriately long molecular length and a high molecular mobility (exhibiting elasticity), the carbon nanofibers move along with the deformation of the elastomer. The aggregated carbon nanofibers are separated by the restoring force of the elastomer due to elasticity, and become dispersed in the elastomer. Expensive carbon nanofibers can be efficiently used as a filler for a composite material by thus improving the dispersibility of the carbon nanofibers in the matrix.